The invention relates to a method and an apparatus for the measurement of the running gears on a motor vehicle, like a passenger car and a truck.
Wheel alignment measurement apparatus in which the measurement procedure is carried out with the aid of a program, are, for example, known from the WO99/23451. Therein, the operator is given instructions and support statements during the wheel alignment measurement so that he can carry out the measurement of the running gears and also the adjustment of the running gears in a proper way taking into account the measurement results. As it is known, the wheels have to be positioned, during the wheel alignment procedure, to different direction positions, for example to xe2x80x9cdriving straight aheadxe2x80x9d, to a turning position of 10 and 20xc2x0 to the left and to the right, respectively, and to equal single track positions left and right. One or the other automobile producer furthermore asks for a positioning according to the maximum turn-around position in order to check whether the turning radius is within a desired range, and/or to hold one of the wheels at 0xc2x0 in order to adjust camber at a track of 0xc2x0. Such turning movements of the wheels are carried out by hand in the known apparatus which is cumbersome because the operator has to leave his servicing location under the vehicle where the adjusting works are carried out, and he has to turn the steering wheel. Only thereafter, the wheel alignment measurement and the adjusting works on the running gears related thereto, can be carried on.
From the EP 0 689 512 B1, a remote controlled device for turning the steering wheel of a motor vehicle is known. The steering wheel can be turned into particular positions by means of this device, and it can be brought back to the zero position. If such a device would be used for the wheel alignment measurement, there is still the problem that the point of time of turning the steering wheel and the amount of the turning of the steering wheel, for example 10xc2x0 or 20xc2x0 to the left or to the right, is selected in error. If the point of time of the turning of the steering wheel is chosen incorrectly, for example at a time when the previous processing step has not yet been finished, there can be errors in the measurement. If the amount of the turning of the steering wheel is chosen incorrectly, the measurement results cannot be compared to the corresponding values in the specifications of the vehicle producers.
It is an object of the invention to be able to carry out the wheel alignment measurement of the running gears in such a way, that the operator is burdened by as few as possible hand operations except of the adjustment of the running gears, wherein, in particular, a correct adjustment of the wheels as to the time and the amount of the positioning is rendered possible.
For achieving this object, the inventive method is characterized in that the wheels of a steerable axis are turned or adjusted, respectively, to the positions required for carrying out the wheel alignment measurement of the running gears by means of a program-controlled, machine-like device. Since the positioning of the wheels is carried out by the program controlled device, the operator does not to have to leave his servicing location for carrying out the positioning of the running gears and the adjustment of the running gears, respectively. Furthermore, the operator has not to reach through the open window on the drivers""s side of the vehicle in order to operate the steering wheel which could result in an interruption of the measurement beam between wheel alignment apparatus devices. Since the positioning of the wheels is directed program controlled, the correct timing and the correct amounts of the positioning of the steering wheel can be defined.
Furthermore, if a platform hoist serves as a servicing location, the measurement and also the adjustment can be carried out while the hoist is on its elevated position without a latter or similar being necessary in order to enable the operator to turn and adjust the steering wheel.
Finally, the operator has to carry out only the absolutely necessary manual operations and adjustments in order to complete the measurement of the running gears and the adjustments thereof, respectively. The operator is, thereby relieved of routine work, and the measurement and adjustment of the running gears becomes more accurate and reproducible.
An advantageous embodiment of the method of the invention is characterized in that the wheels of the steerable axis are turned and adjusted, respectively, to the positions required for carrying out the wheel alignment measurement of the running gears under the control of a central computer of the wheel alignment apparatusor a microprocessor in the machine-like device. If the program control is carried out in the central computer, the capacity which is available there, can be used. If the program control is carried out in the microprocessor in the machine-like device, a direct communication of the machine-like device can be provided to the measurement sensors, for example by means of a communication processor. Since the program is stored in the microprocessor of the machine-like device, the machine-like device only has to be started with a starting command.
An advantageous embodiment of the method of the invention is characterized in that control procedures like for example the automatic positioning of the wheels to xe2x80x9cdriving straight aheadxe2x80x9d, the automatic turning of the wheels to the left and to the right, the automatic positioning to equal single tracks on the left and on the right, the maximum turning position and keeping the wheels on 0xc2x0, are stored in the wheel alignment measurement program. Therein, it is advantageous that the control procedures are, so to speak, stored as sequences in the wheel alignment measurement program and can be called up according to the configuration of the wheel alignment measurement program.
An advantageous embodiment of the method of the invention is characterized in that the control procedures are grouped to groups of control procedures wherein one group of control procedures defines the movement of the wheels of the steerable axis during a wheel alignment measurement. Therein, the above-mentioned control procedures are, for example, put together into a group such that the measurement run as a whole can be called up when it is to be carried out, for example, as a starting measurement or as a control measurement after the adjustment of the running gears.
An advantageous embodiment of the method of the invention is characterized in that the control procedures are put together to measurement runs comprising the evaluation of the measurement values of the running gears prior, during and after the adjustment works on the vehicle. Thereby, the control procedures are put together in an advantageous way so that the wheel alignment measurement of the running gears and the adjustment of the running gears can go on in a unitary program.
An advantageous embodiment of the method of the invention is characterized in that the control procedures are vehicle-specific procedures. In the central computer of the wheel alignment apparatus vehicle specific data are anyway stored for carrying out the measurements with different vehicle types of different manufacturers. The control procedures can, therefore, be added without particular additional expenditure to the vehicle specific data already present. When carrying out a wheel alignment measurement of the running gears, only the correct vehicle type has to be chosen in order to get to correct results.
An advantageous embodiment of the method of the invention is characterized in that the operator is given acoustical and/or optical and/or voice information related to the measurement results, required inputs or/and operations. Thereby, it is achieved in an advantageous way that the operator is always informed about the progress of the wheel alignment measurement of the running gears and that he gets instructions when he can or should carry out which adjustments.
An advantageous embodiment of the method of the invention wherein the measurement of the running gears is carried out on a platform hoist, is characterized in that the control of the hoist is also done by the central computer. It is important also for the control of the hoist that is moved upwards or downwards at the correct point of time. The correct timing of the control of the hoist can also be guaranteed by providing a connection to the central computer of the wheel alignment system.
An advantageous embodiment of the method of the invention is characterized in that specific elevation levels for the control of the hoist are stored also for different operators in the central computer such that the hoist can be moved under the control of the program into positions which are optimized for the respective operator.
An advantageous embodiment of the method of the invention is characterized in that the turning of the wheels by means of the machine-like device or the control of the hoist is carried out only when the operator gives a clearing instruction to the central computer whereby the operator has, in an advantageous way, the possibility to step in if the measurement procedure has to be interrupted, for example in case of an accident or the like.
For achieving the above object, a wheel alignment measurement apparatus for the measurement of the running gears of motor vehicles which carries out the single steps of the running gears measurement under the control of a central computer, is characterized by a program-controlled machine-like device which is adapted to turn and adjust, respectively, the wheels of the steerable axis to the positions required for carrying out the wheel alignment measurement of the running gears.
During positioning and adjustment procedures, respectively, the required turning movements of the wheels can be controlled through operating elements of the wheel aligner system, for example by a keyboard, a remote control, a voice control or the like, whereby an additional operator, who was responsible, up to now, for the turning movements of the wheels of the vehicle is not required anymore.
An advantageous embodiment of the apparatus of the invention is characterized in that the program for controlling the wheels of the steerable axis is stored in the central computer of the wheel alignment apparatusor in a microprocessor in the machine-like device.
An advantageous embodiment of the apparatus of the invention is characterized in that the machine-like device is arranged between the steering wheel of the vehicle at a fixed location on the vehicle and is adapted to turn the turning wheel of the vehicle. This embodiment of the apparatus of the invention has the advantage that the previous procedure in which the turning of the steering wheel was carried out through manipulating the steering wheel, is maintained such that the response characteristic of the vehicle is simulated in an optimal way. The known apparatus is modified so that it can be controlled directly from the central computer of the wheel alignment apparatusor the microprocessor in the machine-like device.
Another advantageous embodiment of the apparatus of the invention is characterized in that a steering wheel level device is arranged on the steering wheel which level is also connected to the central computer of the wheel alignment system or to the microprocessor in the machine-like device and which level outputs the information on the zero position of the steering wheel to the central computer. Thereby, the apparatus can be brought back only under the control of the program and with the information from the steering wheel level device to its starting position (zero position) without additional means being necessary for this purpose on the machine-like devices.
An advantageous embodiment of the apparatus of the invention is characterized in that the machine-like device comprises a motor-driven turntable platforms on which the wheels of the steerable axis of the vehicle are stood. This embodiment of the apparatus of the invention has the advantage that no additional devices have to be mounted within the interior space of the vehicle. Furthermore, no additional devices have to be installed for each wheel alignment measurement of the running gears because the motor drive in the turntable platforms is ready for use any time.
An advantageous embodiment of the apparatus of the invention is characterized in that coupling devices for the wireless transmission of data and instructions between the central computer and the machine-like device are provided on the central computer of the wheel alignment apparatus and the machine-like device, whereby the data transfer between the machine-like device at the central computer can be effected without additional manipulations like plugging in of cables.
An advantageous embodiment of the apparatus of the invention is characterized by a remote control by which a clearing instruction can be given to the central computer in order to actuate the machine-like device whereby the above-mentioned control facility is put into practice in a simple way.
An advantageous embodiment of the apparatus of the invention wherein the wheel alignment measurement of the running gears is carried out on a platform hoist which comprises a control means, is characterized in that the control means of the hoist comprises a interface for transferring data and instructions between the control means of the hoist and the central computer. Thereby, the hoist and the control thereof, respectively, is totally integrated into the wheel alignment system.
A further understanding of the nature and advantages of the embodiments of the present invention may be realized by reference to the remaining portions of the specification and the drawings.